The goal of the project is to increase immunogenicity and protective efficacy of CSP by conjugating a recombinant CSP to recombinant EPA, a carrier protein. Further immune enhancement by novel adjuvants will also be evaluated. Several genes encoding the 3D7 and Indian strains of Plasmodium falciparum Circumsporozoite (CS) proteins have been designed, synthesized, and cloned into an E. coli and P. pastoris expression vectors. Recombinant CS proteins in near full-length were produced. The proteins were conjugated to carrier proteins included a recombinant exoprotein A from Pseudomonas aruginosa. The recombinant CSP was also conjugated to a cross-linked Pfs25 multimer as a carrier. B- and T-cell responses, induced by the conjugates in several formulations were evaluated in rodent models. Biological function of the antibodies were also evaluated by membrane feeding assay. A mouse model using a transgenic berghei parasite expressing falciparum CSP on its sporozoite surface was tested as an assay to evaluate protection conferred by CSP-based vaccines. We are also creating a transgenic knowelsi parasite, expressing falciparum CSP on its sporozoite surface, to establish a monkey challenge model for evaluating protective efficacy of the CSP-based vaccines.